$\"\"$

The polynomial expression is $\"\"$ .

Apply commutative property of subtraction: $\"\"$ .

$\"\"$

$\"\"$ (Combine like terms are grouping)

$\"\"$ (Take out common term n)

$\"\"$ (Take out common term 5) $\"\"$

$\"\"$ (Take out common term $\"\"$ )

$\"\"$ (Rewrite: 4 = 2²)

Apply difference of squares formula: $\"\"$ .

$\"\"$ $\"\"$

The solution is $\"\"$ .